1. Field of the Invention
The present invention relates to image characterization, more particularly, to a method for characterizing texture of areas within an image corresponding to monetary banknotes
2. Description of the Prior Art
The proliferation of image processing systems in recent years, including digital color copiers, scanners, and small scale printing apparatuses, has lead to wide scale use of reproduction of color images and photography. Although mostly used for professional or personal recreation, criminals often try to profit from such equipment through reproduction of currencies, stocks, checks, legal documents, and other documents that are not intended to be reproduced. Due to the existence of such illegal and counterfeit items, there is a need for a method to effectively and quickly characterize and detect illegitimately published currency. This task becomes increasingly more difficult however, as advancements in printing and reproduction quality allow for copies to be made that are virtually indistinguishable to the human eye.
In addition to the increasing difficulties in identifying legitimate currency bills, is the desire to scan sample currencies from images that are larger than the sample currency being scanned. Doing this will allow a bill to be scanned with any common scanner, while possibly allowing the scanning and identification of multiple bills at once. However, doing this introduces more problems as the bills may be presented on arbitrary backgrounds, and may have variations in shift and rotation. Many currency detectors today generally only scan one bill at a time, and only scan the immediate area of the bill in order to omit the need to consider the background, rotation, and alignment of the bill.
Additionally, if the note is scanned while embedded with a complicated image background, it may be very difficult to distinguish the actual note from the image background. The image background may also provide additional noise and/or patterns to complicate the detection process and introduce irregularities and errors.